Telephone apparatus



(N0 Model.) 3 Sheets-Sheet 1. J. B. KER & J. CRAWFORD;

TELEPHONE APPARATUS.

No. 398,243. Patented Nov. 20, 1888.

N. PETERS. Phclo-Lilhugnphcr. WashZn51an,D.C.

3 Sheets-Sheet 2.

D DW. NW m A R m GD... TU.A E w Rm EB m ..T B J (No Model.)

. Patented Nov. .20 1888.

3 Sheets-Sheet 3.

(No Model.)

R W AA R RA w mA m m R m KB .T B J No. 393,243. Patented Nov. 20, 1888.

ii; I.

UNITED STATES PATENT tripe.

JOHN B. KER, OF HARRISBURG, AND JOHN ORrUVFORD, OF READING, PENNSYLVANIA.

TELEPHONE APPARATUS.

SPECIFICATION forming part of Letters Patent No. 393,245, dated November 20, 1888.

Serial No. 234,746. (No model.)

To all whom, it may concern:

Be it known that we, JOHN KER, a British subject, residing at Harrisburg, in the county of Dauphin and State of Pennsylvania, and JOHN CRAWFORD, a citizen of the United States, residing at Reading, in the county of Berks and State of Pennsylvania, havejointly invented a certain new and useful Improve ment in Telephone Apparatus, of which the following is a specification.

The object we have in view is principally to so construct and arrange the parts of a telephone-set that such apparatus can be used in mines of various characters,in chemical works, in military and marine operations, and in like situations where the apparatus will be subject to the action of deleterious gases, or to atmospheric influences injurious to constructions heretofore employed.

In locations of the character indicated it has not heretofore been found commercially practicable to use the telephone as a means of communication between separated points on account of the warping and splitting of the wooden cases of theinstrnments and the rapid corrosion of the metal parts of the mechanism inclosed by such cases, the destruction of the insulation upon the conductors,and the corrosion of such conductors, especially of the call apparatus and those of the induction-coil and their connections. These difficulties are overcome entirely, or to a practical extent, by the construction and arrangement which form the subject of this invention, the bell and transmitter cases being constructed air-tight and of metal, which will itself resist the deleterious atmospheric influences, or will have its surface coated with a protecting material. All the openings into the boxes are protected to make them practically air-tight, and the connections are so made and arranged as to be also protected.

The invention consists in the features of construction and arrangement which we employ to accomplish the object before stated, as hereinafter more fully explained. A specific fea ture ofinvention is a peculiar switching device for controlling the telephone-circuits, which, while especially adapted for use with the air and gas proof instrument, is an efficient construction for general use.

In the accompanying drawings, forming a part hereof, Figure 1 is a front elevation of the bell-box with the cover for the magneto-crank in section; Fig. 2, a view of the bell-box open, with the magneto-crank and cover broken away; Fig. 8, a section on line 3 3 in Fig. 5, showing a part of the switch; Fig. 4, a sec tional view on the line of the magneto-driving shaft, illustrating the means for closing airtight the opening around this shaft; Fig. 5, a side elevation (from the switch side) of the beltbox, such box being partly broken away to show the protection of the bellarn1 opening; Fig. (5, a horizontal sectional view illustrating a modified form of protected switch; Figs. 7 and 8, views of another form of protcctcd switch; Figs. 9 and 10, views of two other forms of protected switch; Fig. 11, a sectional view of a modified manner of protccting the bellarm opening; Fig. 12, an elevation of the end of the telephone-receiver forming a part of my set; Fig. 13, a front elevation of the transmitter-box forming a part of my telephone-set, and Fig. 14 a sectional View of the same through the transmitter.

Like letters denote corresponding parts in all the figures.

The bell-box A and the transmitter-box A each have a body, A, and a cover, A, made preferably of cast-iron coated with asphaltum or tar applied hot to prevent corrosion, although these parts may be made of a metal-- such as lead or nickelwhich will itself stand without injury the atmospheric influences. The bodies and covers of these boxes have a wood lining, B, upon which the parts of the mechanisms are mounted. The covers of these boxes lap over the edge of their bodies when closed, as shown, and a gasket, a, of soft rubber or rubber cloth or other suitable material, is attached to the body or cover at the meeting surfaces, so as to prevent the entrance of air or gas at the joint. All the electrical connections with the inclosed parts of each box are made by means of binding-posts Z). These are mounted upon liard-rubber plates 0, between which and the metal of the box is a sheet, 0, of soft rubber or rubber cloth. Pins 12' on the binding-post project into the hardrubber plate 0 to prevent the posts from turning, while screws b"- pass from the inner side of the wood lining I; through holes in the metal case and through the soft-rubber sheet 0 and the rubber plate 0 into the binding-post, as shown, drawing the binding-post down onto the rubber plate 0 and drawing such rubber plate and the sofarubber sheet tightly against the box. An air and gas tight insulated connection with the interior of the box is thus made. \Vashers under the heads of the screws are used to make the electrical connections within the boxes.

The bell-box A incloses a magneto-generator, O, as usual, for signaling. This is operated by a hand-crank, O, on the outside of the box. To prevent the admission of air or gas into the box around the driving-shaft of the magneto is the object of one feature of construction. An opening is made through the metal body A of the bell-box A and through its wood lining. In this opening is secured a thiinble, d, of hard rubber, in which is secured a metal bushing, d. The face of the thimble d is made concave and the bushing projects beyond it somewhat. Around the bushing in the concavity may be placed a ring, (1 of soft rubber. The hub of the crank O is secured to the end of the drivingshaft G and has a projecting cup or flange, c, which surrounds the projecting end of the bushing (Z and rests,when the parts are not in motion, on the soft-rubber ring (1, closing air and gas tight the opening around the driving-shaft O WVithin the box the driving-shaft O is sup ported in bearings 0 6 so as to be capable of longitudinal movement therein. The end of the shaft outside of bearing 6 has a nut, c, and between this nut and a cup,c", is a spiral spring, e The driving cog-wheel D is sleeved on the shaft 0, its hub having \l-shaped slots engaging with similarly-shaped projections on a collar, f, secured to the shaft 0*. Nowgvhen thecrank-handle is turned, the projections on the collar f give the shaft an outward longitudinal movement against the tension of the spring 6 until stopped by the striking of the nut e on the cup 0*. This lifts the flange e on the crank-hub off of the soft-rubber ring (Z ,I)0II1llbting the crank to be turned without wearing the soft-rubber ring. The collar f may also strike the inner end of the thimble d, thus closing the opening around the shaft from the inside of the box.

upwardly, so that it will close of itself when released, (assisted or not by a spring, f,) and its juncture with the body is constructed, like that on the bcll-box, so as to close air and gas tight.

The preferred form of protected switch has a divided fork for receiving the hand-phone. This fork has a stationary prong, Fl, secured upon a rubber plate, 9, and a movable prong, E, projecting from the lower end of an arm, 9, pivoted to the plate 9 by means of a short shaft, E, which passes through to the interior of the box. A stationary metal bar, F, is secured across the box within the same, near its lower end, and above this stationary bar are three circuit-springs, t, which tend to spring away from the bar F. Another metal bar, F, is arranged parallel with the bar F, and has bail ends which are pivoted to the sides of the wood lining of the box, one of these bail ends being secured to the square inner end of the shaft E. A fourth circuitspring, i, projects above the bar F. Aspring, i on the cover and not forming a part of any circuit, presses on the bar F when the cover is closed and forces that bar down upon thethree springs t, which are forced against the bar F, the bar F at the same time passing out of contact with the spring i. This spring i" by foreing down the bar F turns the shaft E and closes the telephone-fork. IVhen the handphone is hung on the fork, it forces the prongs apart and, through the shaft E, moves the bar F against the pressure of the spring 1", such bar moving from the springs i, which spring out of contact with the bar F, and the bar F at the same time making contact with the spring i. The movement of the swingingbar F between the springst' and t" effects the switching and does it with certainty. The parts of this switching device are simp and not liable to derangement.

Various forms of protected switches may be used which will prevent the entrance of air into the box. In Fig. (i the fork is stationary and a spring puslrpin, G, projects through a protected opening in the box and has a head which enters the fork. The hand-phone,when engaged with the fork,pushes the pin G inwardly, while a spring, it, forces the pin out again when the phone is removed from the fork. This movement of the springpin effects the switching. In Figs. 7 and 8 an axiallyacting fork, G, is employed. This fork is kept in an inclined position by a spring, is, when the hand-phone is in use, as shown in full lines in Fig. 7, and when the hand-phone is hung on the fork the weight of the phone is sufficient to bring it to a vertical position,throwing the fork in so doing into a horizontal position and accomplishing the switching. In Fig. 9 the ordinary form of switch-lever G is employed. This plays vertically in a slot, 7;, in the box, and a protecting-plate, It", held up by a spring, k keeps the opening closed.

Instead of having the lever project through the side of the box, it may stop short of such side, as shown in Fig. 10, and a vertical hook, G pass therefrom through the bottom of the box, the opening around the hook being protected by washers 7;, of soft rubber or other suitable material.

The protection of the opening through IIO which the hammer-rod projects is a matter of importance. By the preferred form of the bell the hammer-rod is arranged to turn axially in the opening, by means of which it passes through the cover of the bell-box, extending at right angles to the cores, instead of parallel with such cores, as is usual. An iron plate, H, is secured to the back of the metal cover of the box, an intermediate rubber sheet, Z, being employed. A rubber plate, Z, is placed on the outside of the box, and a cupnut, I, turns through the parts and clamps the plate H to the metal cover. The magnet K has its yoke m projecting at the ends, and brass rods m project from the ends of this yoke and pass through holes in the plate H, in which they are held by set-screws m The yoke m carries the permanent polarizing-magnet a. The polarized armature a is pivoted upon the plate H, and from its axis projects the bell-arm 0, which passes outwardly through the cup'nut I, and by the vibrating movement of the armature is made to oscillate axially in suchcup-nut. Since it is desirable to hold the armature stationary, in order that the bellarm opening may be protected, the magnet is made adjustable toward and away from the armature by means of the set-screws m and rods m. The cup-nut I is an elbow, asshown in Fig. 5, having a screw-cap, o, it being intended to fill the cup with oil or glycerinc or other viscous substance which will hug the oscillating bell-arm and close the opening air and gas tight. The oil or glycerine may be thickened by condensation or mixed with any suitable substance to make it thick. Outside of the cup-nut I the bell-arm is bent upwardly between the bells L L, which are secured to the outside of the cover.

Instead of protecting the bell-arm opening in this manner, it may be done by the means shown in Fig. 11. In this figure a section of light soft-rubber tubing, M, is bound airtight at one end to a collar, 0, on the bell-arm and at the other end to a thimble, c, on the box". \Vhen so protected, the bell-arm may vibrate in the opening or oscillate axially therein, the section of soft-rubber tubing permitting either movement, while keeping the opening closed air-tight.

In all instances where other than the iron covering is exposed to the atmosphere the ex posed metal parts may be covered by japan, plating, or other preservative preparation.

The hand-phone N is of the usual form.

The comlucting-wircs l 2 leading thereto arenot united in one cord, as heretofore; but these conductors are made as separate flexible cords, as shown, so that the moisture cannot form a cross-circuit between the conductors, as it does when the usual form of cord is employed.

The transmitter-box carrying the transmitter and inclosing the inductioneoil has already been described in its construction.

To prevent the entrance of air and gases by way of the mouthpiece of the transmitter a second diaphragm, 0, is used in addition to the usual diaphragm, l. The diaphragm 0 is fastened airtight at its edges with insulating material on the outside of the case, in front of the ordinary diaphragm. The soundwavcs are transmitted from the auxiliary to the ordinary diaphragm by the intervening body of air. To prevent loss in amplitude of vibration due to the elasticity of the inclosed body of air the two diaphragms may be conneeted at their centers by a light rod, Q, made in sections adjustably connected by a screwsleeve, so that its length can be adjusted to bring the diaphragms into the proper relation and to hold them in that adjustment.

A box, It,with lifting-cover may be used to cover the mouthpiece under some conditions. This box will be like that which maybe used to cover the hand-crank of the bell-boX.

That we claim is- 1. In a telephone-set, the eombination,with the metal bell-box, of the magneto-driving shaft projecting therefrom, such shaft having a longitudinal movement when turned, and means released by such longitudinal move ment and acting when the shaft is at rest to close air-tight the opening around said shaft, substantially as set forth.

2. In a telephone-set, the combinatiomwith the metal bell-box, of the magneto-driving shaft projecting therefrom, a cup-flange on the crank-hub covering a thimble on the box, and means for giving the shaft a longitudinal movement to take the wear from the bearing parts, substantially as set forth.

3. In a telephonc'set, the combinatiomwith the metal bell-box, of the magneto-driving shaft projecting therefrom, a soft-rubber or equivalent packing upon which pressure is brought to close air-tight the opening around the shaft, and means for giving the shaft a longitudinal movement when turned to relieve the packing from wear, substantially as set forth.

4;. In a telephone-set, the combination,with the metal bell-box, of the magneto-driving shaft projecting therefrom, the engaging cogwheel and collar giving the shaft a longitudinal movement, the spring for returning the shaft to its normal position, and means for closing the opening around the shaft when at rest, substantially as set forth.

5. In a telcphoneset, the combination,with the beltbox, of a stationary and a movable metal bar, means for operatingsuch movablcbar by the hand-phone, and circuit-springs forced by one bar upon the other, substantially as set forth.

6. The combination of the metal bell-box, the oscillating beltarm, the packing-cup for a viscous substance, the armature mounted upon a stationary plate, and the magnet-cores adjustably mounted upon such plate, substantially as set forth.

7. In a telephone-set, a metallic instrumentbox and its inclosed mechanism, in combination with bindingposts, a plate of hard insu- IPO IIS

lation upon the outside of the box,upon which This specification signed and witnessed this the binding-posts are mounted, a sheet of soft 7th day of April, A. D. 1887.

or flexible insulation between the plate of JOHN B. KER.

hard insulation and the box, and connections JOHN CRAWFORD. 5 from such binding-posts to the interior of the Witnesses:

box through air-tight openings substantially A. B. WANNER,

as set forth. HOWARD P. WANNER. 

